塔里木盆地原油噻吩类化合物的组成特征及地球化学意义

对塔里木盆地典型原油噻吩类化合物含量和组成特征研究，发现不同类型原油苯并萘噻吩和二苯并噻吩系列化合物占芳烃化合物的百分含量相差明显，海相油含量最高，湖相油次之，而煤成油最低。本文提出了４－甲基二苯并噻吩／二苯并噻吩、（２＋３）－甲基二苯并噻吩／二苯并噻吩比值是区分海相油和湖相油新的有机地球化学参数。二苯并噻吩系列化合物最大烷化度表明海相油呈现出高烷化度，而陆相油则表现为低烷化度，即从海相泥灰岩原油、海相碳酸盐岩原油到湖相油和煤成油依次减少。这是因为富硫与贫硫干酪根在生烃过程中的环化作用或支链化作用程度差异所造成的。

Composition Characteristics and Geochemical Significance of Thiophene-type Compounds for Crude Oils in Tarim Basin

The relative abundance and composition characteristics of thiophene-type compounds for typical crude oils in Tarin Basin were analysed and studied systematically using GC-MS-MS technique. The results suggest the relative abundance between benzonaphiothiophene and dibenzothiophene series of % toatal polycyclic aromatic hydrocarbons for different types of crude oils are obvious differences,the contents of marine oils are the higest,contents of lacustrine oils are lower and that of coal-forming oils are the lowest.In this paper,we propose some new organic geochemical parameters for distinguishing marine oil and lacustrine oil using the ratio values of 4-dimethyldibenzothiophene(MDBT)/dibenzothiophene(DBT) as well as (2+3)-MDBT/DBT,for distinguishing marine marl-sourced oil and marine carbonate-sourced oil using the ratio value of 1-MDBT/DBT.Marine oils and coal-forming oils show a predominance of alkylated DBT homologues over the unsubstituted parent,but laustrine oils differ from marine oils and coal-forming oils.However,the maximum degree of alkylation(the most abundance alkylation homologues within any given DBT series) varies,marine oils show a high degree of alkylation,which non-marine oils generally exhibit a lower degree of alkylation.So there is increasing decrease trends from marine marl-sourced oils and marine carbonat-sourced oils to laustrine oils and coal-forming oils.We propose that alkylation trends reflect differences of crosslinking or branching on aliphatic and cyclic moieties in sulfur-rich vs.sulfur-poor kcrogens.